An inkjet head that ejects ink from nozzles has been known as a liquid ejection device. For example, the known inkjet head includes four flow path substrates, a single communication plate, four nozzle plates, and a plurality of piezoelectric elements. The flow path substrates includes the piezoelectric elements.
Each flow path substrate has pressure chambers that are aligned in two rows. That is, the four flow path substrates include a combined total of eight pressure-chamber rows. The flow path substrates are joined to one of opposite surfaces of the communication plate. The communication plate has manifolds corresponding to the respective pressure-chamber rows. The pressure chambers constituting each pressure-chamber row are supplied with ink from a corresponding one of the manifolds. The nozzle plates are joined to the other of the opposite surfaces of the communication plate. Each nozzle plates includes two nozzle rows corresponding to the two pressure-chamber rows of a corresponding one of the flow path substrates.
Each flow path substrate includes piezoelectric elements on its one surface opposite to its other surface to which the communication plate is joined. The piezoelectric elements are aligned in two rows in accordance with the arrangement pattern of the corresponding pressure chambers. That is, the four flow path substrates include a combined total of eight piezoelectric-element rows corresponding to the eight pressure-chamber rows. A lead electrode (e.g., a lead) is connected to an individual electrode of each piezoelectric element. An end portion of each lead electrode included in adjacent two piezoelectric-element rows extends to an area between the piezoelectric-element rows. In the area between the piezoelectric-element rows, the end portions (e.g., contacts) of the lead electrodes are aligned along a direction in which the pressure chambers are aligned. A wiring member, e.g., a chip-on-film (“COF”), is joined to the contacts. That is, a single wiring member is provided for two piezoelectric-element rows of a single flow path substrate. Thus, the known inkjet head has a total of four wiring members.